Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 334,368	$ 314,684
Accumulated depreciation	(156,524)	(140,240)
Property, plant and equipment, net	177,844	174,444
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	7,543	7,377
Buildings [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	50,607	50,058
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	269,034	252,010
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 7,184	$ 5,239